1. Field of the Invention
The present invention relates to a method and device for location detection, and more particularly, to a method and device for location detection with higher linearity.
2. Description of the Prior Art
A traditional capacitive touch screen typically includes an insulating surface layer, a first conductive layer, a dielectric layer, and a second conductive layer, wherein the first and second conductive layers have a plurality of first conductive strips and second conductive strips, respectively, and these conducting strips are made up by a plurality of conductive pads and connection wires connecting these conductive pads in series.
The changes in capacitances of a plurality of detecting locations on the touch screen can be obtained. These detecting locations correspond to the first conducting strips or the second conducting strips. When an external object approaches or touches the touch screen, a profile corresponding to the external object will appear in the changes in capacitances as shown in FIG. 1A, for example. A coordinate data (a location) corresponding to the external object can then be calculated based on some or all of the values in the corresponding profile. For example, a centroid location is calculated based on the largest three values or all of the values.
In a profile, the largest value will have the biggest influence on the coordinate location. For example, in FIG. 1A, the coordinate data is calculated from the largest value and values at either side (the preceding and the following values). Since the peak (it may be referred as relative high point hereinafter) of this profile is at the third value, the coordinate data will be close to the coordinates of the third value.
However, during the movement of an external object, the peak will shift from one value to other neighboring values, for example, as shown in FIGS. 1B and 1C. As the largest value influences the coordinate value the most, with respect to the actual location of the moving external object, the coordinate data will result in the detected movement to be slowing down then speeding up and then slowing down again. As a result, poor linearity shown in FIG. 1D will occur.
From the above it is clear that prior art still has shortcomings. In order to solve these problems, efforts have long been made in vain, while ordinary products and methods offering no appropriate structures and methods. Thus, there is a need in the industry for a novel technique that solves these problems.